In an image processing apparatus which internally generates two types of image data (“image data 1” and “image data 2”) from one input image, processes these image data, then further processes the image data and outputs them via an external bus, the “image data 1” is temporarily stored in an image buffer, then subjected to image processing by an image processor, and the “image data 1” is transferred to an external storage device via the external bus. The processing on the “image data 1” is continued until all the “image data 1” for one frame has been processed and transferred to the external storage device.
On the other hand, while processing of the “image data 1”, the “image data 2” is generated and processed and then stored in the image buffer, thus all the “image data 2” is stored into the image buffer.
Then, when the image processing on the “image data 1” and data transfer of the “image data 1” have been completed, the image processing apparatus issues an interrupt request (exceptional processing request) to an external (other than the image processing apparatus) controller (e.g. CPU) connected to the external bus. In response to the interrupt request, the external controller performs re-setting on the image processing apparatus for processing the “image data 2”. When the re-setting processing has been completed, the processing on the “image data 2” is started in the image processing apparatus. The “image data 2” is read from the image buffer, subjected to the image processing by the image processor, and transferred to the external storage device via the external bus.
Further, when the image processing on the “image data 2” and data transfer of the “image data 2” have been completed, the image processing apparatus again issues an interrupt request to the external controller. In response to the interrupt request, the external controller performs re-setting on the image processing apparatus for processing the next input data.
In this conventional image processing apparatus, since the image processing on the “image data 2” is started after the completion of data transfer of the “image data 1” to the external storage device, suspension time of the image processing before the start of image processing on the “image data 2” becomes long, and efficiency of the image data processing is low.
Further, the controller, connected to the external bus on which the image data is transferred, starts reception processing by the interrupt indicating a request for reception of processed image data, issued from the image processing apparatus which has processed the image data. Accordingly, in the controller, the processing which has been performed by that moment is suspended, and efficiency of processing is degraded.